THERMAL EXPANSION VALVE

A thermal expansion valve (often abbreviated as TEV, TXV, or TX valve) is a component in refrigeration and air conditioning systems that controls the amount of refrigerant flow into the evaporator thereby controlling the superheating at the outlet of the evaporator. Thermal expansion valves are often referred to generically as "metering devices".
Flow control, or metering, of the refrigerant is accomplished by use of a temperature sensing bulb, filled with a similar gas as in the system, that causes the valve to open against the spring pressure in the valve body as the temperature on the bulb increases. As the suction line temperature decreases, so does the pressure in the bulb and therefore on the spring causing the valve to close. An air conditioning system with a TX valve is often more efficient than other designs that do not use one.
A thermal expansion valve is a key element to a heat pump; the cycle that makes air conditioning, or air cooling, possible. A basic refrigeration cycle consists of four major elements, a compressor, a condenser, a metering device and an evaporator. As a refrigerant passes through a circuit containing these four elements, air conditioning occurs. The cycle starts when refrigerant enters the compressor in a low pressure, low temperature, gaseous form. The refrigerant is compressed by the compressor to a high pressure-and-temperature gaseous state. The high pressure-and-temperature gas then enters the condenser. The condenser precipitates the high pressure-and-temperature gas to a high temperature liquid by transferring heat to a lower temperature medium, usually ambient air. The high temperature liquid then enters the expansion valve where the TX valve allows a portion of the refrigerant to enter the evaporator. In order for the higher temperature fluid to cool, the flow must be limited into the evaporator to keep the pressure low and allow expansion back into the gas phase. The TXV has sensing bulbs connected to the suction line of the refrigerant piping. The sensing bulbs give temperature readings to the TXV to adjust flow of refrigerant.

FUNCTION IN A REFRIGERATION CYCLE

Expansion valves are flow-restricting devices that cause a pressure drop of the working fluid. The valve needle remains open during steady state operation. The size of the opening or the position of the needle is related to the pressure and temperature of the evaporator. There are three main parts of the expansion valve that regulate the position of the needle. A sensor bulb, at the end of the evaporator, monitors the temperature change of the evaporator. This change in temperature creates a change in pressure on the diaphragm. For example, if the temperature in the evaporator increases, the pressure in the diaphragm increases causing the needle to lower. Lowering the needle allows more of the working fluid into the evaporator to absorb heat. The pressure at the inlet of the evaporator affects the position of the needle and prevents the working fluid from flowing back into the compressor. Since the pressure before the valve is higher than the pressure after the valve, the working fluid naturally flows into the evaporator. The pressure at the inlet of the evaporator acts on the diaphragm. There is also a spring providing a constant pressure closing the valve needle. The spring constantly restricts the amount of working fluid entering the evaporator. The pressure spring can be adjusted to increase or decrease pressure based on temperature needs. The pressure created by the spring acts on the opening of the valve. When the pressure of the sensor bulb acting on the diaphragm is greater than the combined pressure of the evaporator and spring, the valve opens to increase the flow of the working fluid. An increase of flow lowers the temperature of the evaporator and allows for more heat absorption.

TYPES OF THERMAL EXPANSION VALVED

There are two main types of expansion valves: internally or externally equalized. The difference between externally and internally equalized valves is how the evaporator pressure affects the position of the needle. In internally equalized valves, the evaporator pressure against the diaphragm is the pressure of the outlet of the expansion valve, whereas in externally equalized valves, the evaporator pressure against the diaphragm is the pressure of the outlet of the evaporator.

Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about Indoor Air Quality and other HVAC topics, click here to visit our website.

HAPPY BIRTHDAY - TRANE

A STATEMENT FROM TRANE ON THEIR 100TH BIRTHDAY:

When you have a 100-year legacy of partnership, it’s easy to predict how Trane will work with you in the future. Just as we work with you now to deliver innovative products, systems and services that meet your needs, our partnership will continue going forward to develop innovative solutions that address your growing concerns about the environment, energy efficiency and sustainability. Research in renewable energy technologies, advancements in energy management services, and best practices in energy conservation today will define the future of energy use for generations to come. At Trane, we see more than a building. We see opportunities to build life, and lead the industry for the next 100 years.

Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about Indoor Air Quality and other HVAC topics, click here to visit our website.

Is That Normal? Sound Advice About Air Conditioner Noise

Sometimes our cars, appliances, and even air conditioners make the strangest noises, but how do you know if they’re normal or if something might be wrong? It’s not always as easy as hitting the ‘restart’ button on your computer, so it’s important to know when you should call a professional or contractor to check it out. The following are some tips about what sounds are normal and what indicates professional problem when it comes to your air conditioning unit.

Outdoor unit noise is normal upon start-up and shut down. The outdoor unit is where most of the mechanical operations in your system take place and depending on the type of equipment, it can be noisy and somewhat varied when it starts up and/or shuts down. Typically, most air conditioners make noise when they first cycle on, which can be caused by the buildup of pressure in the refrigerant lines or from bearings, fans or other moving pieces starting up. The same is true when the unit cycles off, or comes to a stop, as the pressures need to equalize. Sometimes this causes a unique noise that sounds like air escaping, a click or rattle.
◾Tip: If the start-up and shut down sounds are the same from cycle to cycle and not too loud, it’s probably normal and not worth calling a contractor.

Outdoor unit running noise after start-up can also vary among different types of equipment. Once the outdoor unit starts up, it should reach a consistent sound where you hear the fan blowing and the other mechanical parts humming along. Sometimes you might hear a cycling sound over the period of a few seconds where the unit changes the pitch of its normal running sound and might get louder or quieter in “waves.” If it gets increasingly louder as the system is running, then it might require a contractor to see whether it is out of balance or requires further inspection. If you hear a loud, intermittent mechanical “scraping” or “banging” noise, this is not normal and you should shut your system down and call a contractor to inspect it as soon as possible.
◾Tip: Significant changes in pitch or ‘banging’ noises indicate you should call a contractor.

Indoor unit sound is usually the sound of the fan moving air through your system. It is most noticeable when the system turns on and off. If you have a high efficiency system (16 SEER and over) you could hear two distinct sounds as your system moves from high to low cooling speed. The high speed sound can be noticeable, but the low might be so quiet you can barely hear it.
◾Tip: Air moving through your system should sound smooth and consistent once it is running.

In general, sound is a subjective attribute and the above descriptions are provided as a guideline for noises that could potentially signal a costly problem. In addition, we have recorded some typical compressor sounds you might hear during a normal start up, run and shut down cycle as examples

Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about Indoor Air Quality and other HVAC topics, click here to visit our website.

Duct System Design: Get it Right From the Get-Go or Try, Try Again

The efficiency of the cooling equipment in your northeast Florida home is directly tied to your duct system design.

If the ducting isn’t properly planned, the distribution of your air affects your comfort, the quality of your indoor air and your energy costs.

New Home Duct System Design

Years ago, the ducting system was installed almost as an afterthought. Poorly distributed ducts exist in millions of older homes and are costing homeowners with needlessly higher energy bills. In recent years, however, energy-conscious architects and home builders have become aware of how important duct design is for new homes. Basic supply duct configurations get more attention in early planning stages than they did previously, maximizing the efficiency of present-day heating and cooling systems.

Problems With Poor Airflow

A poorly planned duct system design can result in airflow problems that a homeowner may never have a clue about. Depending on the age of your home, having a professional evaluation and altering your ducts could potentially result in significant savings in annual energy costs. Here’s a list of some of the common problems homeowners face:

•Too few supply or return vents in rooms
•Long runs of incorrectly sized ducts to distant rooms
•Sharp turns or junctions where airflow is slowed
•Exposed ducts that aren’t sealed inside conditioned spaces
•Bad seals at delivery and return vents

Ideally, all ducts should be contained in conditioned spaces. If this isn’t possible, they should be well insulated. Ducts should be configured so that there are easily graduated turns which don’t interfere with the velocity of the air. If the air speed slows, poor distribution throughout the home can result.

These are all problems resulting in higher costs and lower comfort.

If you’d like more information about how your silent and hidden ducts should work, contact the experts at Ation Heating and Air Conditioning. We’re happy to help educate you about the value of good duct system design, as well as answer any other home comfort questions you may have.

Website Seeks Illegal R-22 Information

A Website has been set up to allow browsers to report what they consider illegally sold HCFC-22. “If someone offers you an incredible deal on R-22, it likely is too good to be true,” is part of the statement on the home page of www.klexserve.com/catch22 for its Catch-22 Compliance Line.

The statement goes on to say, “Don’t help perpetrate a crime and put yourself in jeopardy at the same time.” Browsers are directed to a link asking for the submitter’s name, address, and phone number - although the submitter does not have to provide that info - and then asks for details about the possible illegal refrigerant.

“Buying and selling R-22 is a regulated activity,” the site said. “Only those authorized under the Environmental Protection Agency’s Clean Air Act can do so. Companies with authorized allowances given by the EPA want to make sure that the R-22 market is a level playing field for all participants. Buying and selling R-22 is a regulated activity, and only those authorized under the Environmental Protection Agency’s Clean Air Act can do so.”

The site asks for details on the refrigerant in question as well as where and when it was purchased.

At the site, Klexserve is described as “the legal process outsourcing entity of the Kochhar Group, a leading and pre-eminent Indian group specialized in providing diversified services of global and international standards to multinational corporations and their Indian subsidiaries, including several Fortune 500 companies based out of North America, Europe, Canada and Japan.” The site does not make clear whom Kochhar is outsourcing for in this case, although the refrigerant manufacturer Honeywell issued a press release on Feb. 18 saying it “has provided financial support for the Website.” Other refrigerant manufacturers are doing the same, it has been reported.

In its press release, Honeywell said, “the Website (is) aimed at curtailing unauthorized sale or purchase of R-22. The Website allows users to report suspected sale or purchase of the refrigerant, providing information so that authorities can investigate further.”

DuPont issued a statement on Feb. 19, saying, “DuPont has joined forces with other major industry manufacturers to simplify the reporting of R-22 buying and selling activity that is not in compliance with federal rules and regulations. Those who illegally transact R-22 in the U.S. are subject to seizures of the product, large fines and, as evidenced in the recent smuggling operation in Florida, prison sentences. Protect yourself by knowing your refrigerant source. Report known or suspected cases of illegal R-22 activity.”

The site also has a phone number, (866) 506-6134

Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about Indoor Air Quality and other HVAC topics, click here to visit our website.

Efficiency of Geothermal Attracts Nonresidential Users

Geothermal Technology Offers Long-Term Cost Savings

Some interesting breaking news from The Air Conditioning|Heating|Refrigeration News.



With heating and cooling accounting for 40 to 50 percent of power consumption in nonresidential buildings, it highlights the need to increase energy efficiency in these buildings, and geothermal heating and cooling may hold the key, according to a new analysis from Frost & Sullivan.
“Geothermal heating and cooling is an excellent way to conserve energy while employing the earth as the chief energy transfer base,” said Konkana Khaund, Frost & Sullivan energy and environment industry manager. “Despite its huge initial costs, its higher energy efficiency and long-term cost savings are capturing the attention of environmentally conscious end users.”

Frost & Sullivan noted that the geothermal market is reined back by the high capital required to install the technology.

“Nonresidential users are in a better position to invest the capital and gain strong returns on investments in just a couple of years,” said Anu Cherian, senior industry analyst. “However, most end users are inclined towards ‘short termism’ and do not perceive the long-term benefits of investing in this technology.”

Apart from tight spending from end users, the highly competitive geothermal heating and cooling market is also challenged by price wars. To differentiate, Frost & Sullivan said manufacturers need to educate their potential end users about the lifecycle cost savings that can be accrued by investing in geothermal technologies. Installing such environmentally friendly products will also make building owners eligible for tax rebates and incentives.

Overall, geothermal heating and cooling technology’s benefits are expected to attract customers from across segments. Some of these benefits include long lifecycles, reliability, decrease in energy cost, the ability to comply with energy efficiency requirements, and the positive impact on the environment.

Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about Indoor Air Quality and other HVAC topics, click here to visit our website.

Toren Partners LLC: Camera System, Extension Pole

We find it interesting to share with our readers, the new equipment that is available to our industry.

Made of stainless steel, the Swift Hitch camera extension pole enhances usage of the Swift Hitch wireless portable backup camera system. The pole extends to 5 feet, is easily attached to the base of any Swift Hitch camera, and features an adjustable camera angle. The pole allows the camera to view otherwise inaccessible areas such as crawlspaces and attics; over walls; and under staircases, foundations, and porches, while providing the user with a clear image on a hand-held monitor. It can be used in a variety of applications including HVAC inspections, electrical inspections, home inspections, plumbing, duct cleaning, and monitoring construction progress. The SH01 model camera system features a camera with a four-hour built-in rechargeable battery, while the SH02 model offers a camera with a 10-hour built-in rechargeable battery. Both cameras have a magnetic base. Each system comes with a hand-held full-color high-definition monitor.

Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about Indoor Air Quality and other HVAC topics, click here to visit our website.